Current available heat pump has low efficiency under low temperature working condition. The current defrosting methods such as electrical defrost system and reverse-circulation defrost system require the heat pump to stop operation while defrosting. Therefore, it is the primary objective of the present invention to provide an air-condition heat pump capable of uninterrupted operation during defrosting.
In general, current heat pump has very limited range of working temperatures due to operation efficiency. However, outdoor temperature may vary from negative 40 degree Celsius to 10 degree Celsius, therefore it is another objective of the present invention to provide a wide range air-condition heat pump capable of operating under wide range of working environment temperature at high efficiency.